Gangue is primarily made of silicate minerals, quartz, limestone, clay, and other non-metallic rocky materials that have no commercial value in ore extraction.
Common Gangue Compositions:
1. Silicates:
- Silicon dioxide (SiO₂/quartz) - most common
- Feldspars
- Mica
- Clay minerals
2. Carbonates:
- Calcium carbonate (CaCO₃/limestone)
- Magnesium carbonate (MgCO₃)
- Dolomite
3. Oxides:
- Aluminum oxides
- Iron oxides (when not the desired ore)
- Titanium dioxide
4. Other Materials:
- Sand particles
- Soil components
- Rock fragments
- Phosphates (in some ores)
Composition Varies By:
- Type of ore deposit
- Geological formation
- Geographic location
- Mining environment
Characteristics:
- Low melting point compared to metals
- Non-metallic properties
- Lower density than ore minerals
- Variable chemical composition
Key Takeaways:
- Primarily silicates and carbonates
- Composition depends on ore type and location
- Removed as waste during ore concentration
- Must be separated to improve ore quality